The government is paying out tens of millions of pounds in redundancy packages to civil servants at the same time as it spends millions of pounds recruiting agency staff to fill vacant posts across Whitehall, according to new figures.

He said the government was in a "headlong rush" to casualise the service and cut jobs regardless of whether or not the posts would need to be refilled, wasting tens of millions of pounds of taxpayers' money.

"In its casual approach to managing public sector reforms, there is a danger that the Tory-led government will inflict lasting damage on the services upon which we all depend," said Trickett. "Guided by the crude dogma that cheapest is best, the truth is the government is actually costing the tax payer more."

In an article for Comment is Free, Trickett warned that if the current rate of cuts continued over the lifetime of the parliament taxpayers would face a bill of more than £1bn in redundancy payments.

"What is staggering is that there appears to be no proper control over which posts need to be replaced and which do not," said Trickett. "It is clear that the government's left hand does not know what its right hand is doing."

The Labour MP added that the figures, which came in answers to a series of parliamentary questions, were just the tip of the iceberg in terms of redundancy costs, with hundreds of thousands of public sector jobs under threat.

"Civil servants make up only one tenth of all public sector employees. The office of budget responsibility has estimated that in the wider public sector 710,000 public employees will be laid off."

The warnings were echoed by trade unions which said the government cuts were driving down pay and conditions and undermining public service ethos by casualising the workforce.

Mark Serwotka, general secretary of the Public and Commercial Services Union, which represents civil servants, said: "The government is rushing to making cuts for ideological reasons without any thought about the long-term effect on services or costs. It is more efficient, and better for the economy as a whole, to keep public servants in secure jobs with decent pay. We will not resolve the deficit by cutting jobs and wages."

Dai Hudd, the deputy general secretary of Prospect, which represents senior civil servants, said there was a long-term skills shortage within the service that was being exacerbated by the cuts.

"We are seeing an accountant-driven set of redundancies and to put it crudely senior civil servants are ignoring the skills and simply taking anybody that puts their hand up.

"What we are seeing is the privatisation of public sector work by stealth because when ministers come back and ask whether the civil service has the skills to perform a specific task, surprise, surprise the senior civil servants say 'well no we don't, minister' because they have let many of the high-skilled people go. Therefore we land up with increased pressure to outsource, often at quite considerable cost."

A spokesman for the Cabinet Office minister, Francis Maude, accused Labour of hypocrisy.

"They presided over a redundancy scheme where civil servants could receive over six times their salary in redundancy pay. We have cut this down drastically and also cut their wasteful consultancy and agency spend by over £1bn. It is outrageous that they are criticising the coalition government for clearing up the inefficiency Labour left behind."

But Trickett said the government was in danger of losing control of staffing costs within the civil service. "In their ideological haste to downsize the state and attempt to reduce expenditure, the Tory-led government are costing the country dear, not just financially but in skills morale and expertise."